US2008373A - Precipitating copper from solutions - Google Patents

Description

July 16, 1935. H. A. TOBELMANN PRECIPITATING COPPER FROM SOLUTIONS Filed July 30, 1952 INJLL'MW Q\ ZOC'DJOW @02725.

Patented July 16, 1935 'i UNITED STATES u 2,008,373 PRECIPITATING COPPER FROM SOLUTIONS I leA'rlni'lV orties HenryAf'Iobelmann, Salt Lake City, Utah f Application July 30, 1932, serialNo. 626,781

operation and sequences of operations set forth in this specication, and the features for which protectioniof Letters Patentof theUnited lStates is desired, are collectively grouped in the `claims concluding this specification.

The drawing, consisting of a single figure, illustrates'in1.diagrammatic'form, plant apparatus by means of which the process `is carried into practice. f

I have observed that copper solutions resulting from lixiviation operations, `also contain other elements and/or` compounds, such as iron, alumina, lime, magnesia, silica, acids, etc. In nearly all cases, iron is present in suchr solutions in both the bivalent andtrivalent forms.` 'Ihe trivalent form is a ready solvent of metallic copper and metallic iron. The product obtained when subjecting" solutions resulting from the lixiviation of copper ores or otherwise to the action of 'metallic iron, is generally designated in the art, as Vcement copper.

The cement copper so obtained, consists of individual particles of copper largely in the me' tallic` form, together with various impurities in a more or less iinely divided state. Y*

As the solution becomes impoverished in copper, I'have observed that'there is a gradual diminution in both the quantity and the quality of thecement copper precipitated. Y Furthermore, as the quality or grade or" the cement copper becomes poorer, the amount of copper present in a slimy or colloidal form, increases. The finely divided portion includes more or less of the impurities present in the solution. .However, all cement copper invariably contains more or less finely divided material which carries a large part of the impurities. The proportion of this iine material increases as the copper content of the( the ferrie ion to the ferrous.

portion of the cement copper may be removed by subjecting all orl a part of the precipitate, in a mechanical agitator of one kind or another, with a suitable solution derived from leaching or other operations, and containing ferrie or trivalent iron. The solution will hence forth be referredA to herein as the head solution.

vThe activity of the head solution as a solventV of copper is largely dependent on the trivalent iron, for example, in the case of a sulphate solution, ferrie sulphatethat may be present according to the reaction:

By` proper manipulation, only the ner and more impure portions of the precipitate will be dissolved, resulting in a proportional reduction of This enriched and Vsimultaneously reduced, or partly reduced, solution from the agitator, is readily separated from the undissolved or coarser parts of the precipitate, and` is then deliveredto the head of the precipitation plantuwhere the dissolved copper Vis recovered accordingy to the following reaction:

The impuritiespresent as `a part of the fine precipitate, such as metallic iron, silica, etc., will either be dissolved or carried away by the natural flow-oi the solution, asdetermined by the f duction expedients `may be employed, such y.

treatment With sulphur dioxide. The' complete reduction of the ferrie ion in the head solution, to` ferrous, Aby either or both of these methods, will mean a saving in the poundage of iron consumed per lb. of copper precipitated, and thus, the objectionable ferrie ion, in whatever quantity it may occur in the head soluti-on, is directed toy the useful purpose of dissolving the lower grade cement copper.`

The drawing illustrates `what has just been explained. Referring to the drawing, the portions ID and I2, indicated in broken lines, represent the apparatus usually used in the simple process of precipitating copper from solution as r generally carried oirheretofore.

'Ihe portion i0 denotes the customary copper precipitation tanks, which consist of a plurality of successive sections with the head solution entering at one end and the waste or tailing solution leaving at the other end, while l2 denotes vtions of 4storage tank the customaryxcopper precipitate storage tanks, which latter have sections corresponding to the sections oi the precipitation tank. The data appearing `in the storage tank sections of the drawing, denote quantities of precipitate and the percentages of the respective copper and moisture .contents as taken from an actual case in practice, the copper content noted, being natu-V rally based on the dried sample. This is for purposes of illustration only. l

The portions of the drawing shown in iull lines, indicate a typical installation -o the ap- Yparatus that may be added to an ordinary precipitation plant in order to achieve the benets of my improved process. It is oi courseunderstood that the data shovvnv in the successive sec- !2, will be `materially changed by the operation of my process.

In my process, the usual head solution con-v nely divided metallic copper and metallic iron present in theprecipitate, thereby reducing the ierric ion to ferrous. rhe solution from agitator I5 is taken to a suitable device for settling the heavier particles, such as a settler or thickener l1, from where the enriched solution with little Y or no ferrie ion and little or nol metallic copper,

is taken through a conductor i8 to the head of the copper precipitation plant where the copper is .precipitated under the usual conditions. Under certain conditions of operation, it may be found desirable toV resort to sulphur dioxide or some other reducing agent in order to assure complete reduction of the ferrie ion, Yparticularly when for one reason or another, the quantity o f ferrie ion present in the head solution is in excess of the quantity of copper it is desired to dissolve. In the latter case, the solution passing from the settler Il in conductor i8, may be by-passed through Aa conductor i9 leading toa sulphur dioxide or other suitable reduction plant.

In case any of the precipitate from the head Vend of the storage I2, is sufliciently high grade to maketreatment unnecessary, it may be taken through a conductor 2l directly to container 24 for final disposition or other processing.

The cement coppenjirom which the iine` portion has been dissolvedin the agitator i5,is

,Washed by` a spray ofV Water `225, and delivered into container 24 through a conductor 26.

Having fully described my invention, vwhat I claim is:

1. The method of purifying cement copper consisting in separating the fine portionV from the coarse portion, redissolving the copperin the ne portion by means of a ferrie salt and passing the redissolved portion back to the head of the precipitation system for reprecipitation.

2. A process forV precipitating copper from solutionscontaining iron in the ferrie or trivalent state, including the step which consistsin passing the head solution through a series of successive containers containing metallic iron, to

creasing .the copper content of cement copper or impure metallic copper precipitate, including the cycle which consists in subjecting the said impure precipitate to the action of a solution containing iron in the trivalent or ferrie state, thereby dissolving all or a part of the fine metallic portion Vof the precipitate, and returning the now enriched copper solution to the head of the precipitation system. i

5. A process for purifying cement copper or impure metallic copper precipitate occurring in a'precipitation system, including the step which consists in subjecting-the said impure precipitate to the action of a solution containing iron in the trivalent or ferrie state, thereby dissolving the fine VVportion of the said impure precipitataand returning the now enriched copper solution to the head of the precipitationsystem.

6. `In a precipitation system, a process for decreasing the tendency of cement copper to oxidize, including the cyclic step which consists in subjecting the whole or part of an impure copper precipitate to the action of aV solution containing iron in the trivalent or ferrie state, thereby removing by dissolution part or all of the very fine or slimy portion of the said impure precipitate, which portion has the greatest tendency to oXidize, and returning the enriched solution to the head of the precipitation system. Y

HENRY A. TOBELMANN.

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